METHOD FOR MANUFACTURING A ROTOR FOR AN ELECTRIC ROTATING MACHINE

Description

[0001] The invention relates to a method for manufacturing a rotor for an electric rotating machine.

[0002] The invention further relates to a rotor for an electric rotating machine, which is manufactured using such a method.

[0003] The invention further relates to an electric rotating machine with at least one such rotor.

[0004] Such a method is used in particular for the manufacture of rotors for high-speed rotating electric machines, which are, for example, designed as asynchronous machines. For example, such a high-speed rotating electric machine can be operated with a power output of at least 1 megawatt and a rotational speed of at least 5000 rpm; however, the invention is not limited to such machines. A high-speed rotating electric machine can be operated as a motor or as a generator, for example in a compressor or a turbine.

[0005] The rotor has at least one magnetic pole-generating element, for example a squirrel cage, a winding or permanent magnets, which must withstand the centrifugal forces occurring at high rotational speeds.

[0006] The patent application EP 2 979 349 A1 describes a method for manufacturing a rotor of an electric machine, wherein the rotor has a rotor core made of a core material arranged concentrically to the rotor axis, wherein the rotor core has slots which extend substantially in the axial direction, wherein the rotor core has at each axial end of the slots an annular recess arranged concentrically to the rotor axis which connects the slots, wherein the rotor core has a diffusion layer which comprises a diffusion material and which at least partially covers the respective surface of the slots and / or the respective annular recess.

[0007] Patent EP 2 979 350 B1 describes a method for manufacturing a rotor for an electric asynchronous machine. In this method, a carrier shaft with grooves is produced. A squirrel-cage rotor is mounted onto the carrier shaft. The carrier shaft and an electrically conductive bulk material are placed in a container so that the bulk material fills the grooves. The bulk material is compacted in the container by hot isostatic pressing and bonded to the carrier shaft.

[0008] The German patent application EP 3 040 384 A1 describes a rotor shaft for a high-speed motor, wherein the rotor shaft comprises a shaft body designed for rotational motion during operation of the high-speed motor. The shaft body is made of a steel material. The rotor shaft further comprises a coating attached to at least a portion of an outer surface of the shaft body, the coating being designed to conduct an induced electric current for the rotational motion of the shaft body. The coating is made of an alloy material, wherein the alloy material of the coating and the steel material of the shaft body are different materials.

[0009] German patent application DE 10 2012 006 248 A1 describes a squirrel-cage rotor and a manufacturing process for it, wherein the rotor has conductors of sufficient thickness. In the invention, conductor particles are sprayed onto a core and / or conductive rods in a solid state. As a result, the enlargement of the crystal grain of the conductors in the cover layer material is significantly limited, thereby bonding conductive end rings to the core and / or the conductive rods.

[0010] German patent application DE 10 2009 053987 A1 describes a method for manufacturing a compact and / or solid multilayer coil. Electrically conductive connections are created between the individual conductor layers embedded in the substrate material, in particular between the individual conductor tracks, using dynamic cold spraying.

[0011] The patent application WO 2016 / 017256 A1 describes an induction motor having a rotor with busbars contained in slots of a solid iron core. The slots are open slots and have a width that gradually and linearly tapers from the outer circumference to the inside of the rotor.

[0012] The European patent application EP 0 264 110 A1 describes an electromagnetic arrangement, in particular an electromagnetic winding with electrically insulated conductor turns, which are insulated from each other and have the form of an electrically conductive film. The film can be a metal coating on an electrically insulated plastic film or consist of electrically conductive plastic with an insulating layer between the individual turns of the winding.

[0013] From JP2014108006A a rotor with a squirrel cage is known which has slots for conductors of the squirrel cage, wherein printed metal powder is used to form the conductors.

[0014] From EP 0264110 A1, an electromagnetic arrangement, in particular an electromagnetic winding with electrically insulated conductor windings, is known, which are electrically insulated from each other and have the form of an electrically conductive film.

[0015] From DE 102005056823A1 a method for manufacturing a magnetic device of an electric machine is known, in which one or more permanent magnetic areas are produced on a magnetic carrier of the magnetic device by applying a magnetic material as a powder.

[0016] The invention is based on the objective of providing a method for manufacturing a rotor for an electric rotating machine which is simpler and more cost-effective compared to the prior art.

[0017] This problem is solved according to the invention by a method for manufacturing a rotor for an electric rotating machine with at least one shaft body and a squirrel cage according to claim 1, wherein a coating made of at least a first metallic material and a second metallic material which differs from the first metallic material is sprayed onto at least a part of a substantially cylindrical outer surface of the shaft body by means of a thermal spraying process, wherein at least a part of the squirrel cage is formed by the coating.

[0018] Furthermore, the object of invention is solved by a rotor for an electric rotating machine according to the claim, which has a squirrel cage and is manufactured using such a method.

[0019] Furthermore, the problem is solved according to the invention by an electric rotating machine according to claim 13 with at least one such rotor.

[0020] The advantages and preferred embodiments listed below with regard to the method can be applied analogously to the rotor and the electrical rotating machine.

[0021] The invention is based on the idea of ​​optimizing the manufacturing of a rotor for an electric rotating machine by using a thermal spraying process. Examples of thermal spraying processes include arc spraying, plasma spraying, and flame spraying. Various metallic materials are sprayed onto a substantially cylindrical outer surface of a shaft body using the thermal spraying process, forming a dense and firmly adhering coating. This coating forms at least part of a magnetic pole-generating element. A metallic material is, for example, a metal or an alloy with hard magnetic, soft magnetic, or non-magnetic properties. A magnetic pole-generating element is, for example, a squirrel-cage magnet, an electromagnet, or a permanent magnet.When both metallic materials are sprayed onto the shaft body, the interlocking between the materials is improved by forming a metallurgical bond, thus securing the magnetic pole-generating element against, for example, centrifugal forces occurring during operation. In particular, compared to hot isostatic pressing, the thermal spraying process significantly reduces the number of work steps, leading to a simplification of the manufacturing process and a reduction in production costs.

[0022] Cold gas spraying is a particularly advantageous thermal spraying process. In cold gas spraying, solid particles accelerated by a gas stream strike the wave body with such high kinetic energy that a metallurgical bond is formed via diffusion mechanisms. Compared to other additive manufacturing processes, cold gas spraying allows for the rapid and geometrically flexible production of thick layers, for example, in the millimeter and centimeter range. Because the material applied by cold gas spraying is not melted but deformed by its kinetic energy, thermally induced stresses, especially in the bonding area, are largely avoided.

[0023] In a preferred embodiment, the second metallic material is a soft magnetic material. Soft magnetic materials include, for example, iron or steel, which are suitable for conducting a magnetic flux within the material. If the soft magnetic material is sprayed on together with the first metallic material, machining the shaft body is simpler, as, for example, no grooves need to be milled. Furthermore, the interlocking between the materials is improved by forming a metallurgical bond, thus securing the magnetic pole-generating element, for example, against centrifugal forces occurring during operation.

[0024] In a preferred embodiment, the shaft body is made of the second metallic material. Particularly when the second metallic material is a soft magnetic material, the electrical properties of the rotor are improved and simulation of its electrical behavior is simplified. Reducing the number of materials results in cost reduction.

[0025] In a further advantageous embodiment, at least part of a squirrel-cage cage is formed by the first metallic material. For example, bars of a squirrel-cage cage are formed from a first metallic material which, together with the second metallic material, is sprayed onto the shaft body, with squirrel-cage rings being connected to the squirrel-cage bars at their axial ends. Such a squirrel-cage cage is easy and inexpensive to manufacture.

[0026] In a preferred embodiment, the squirrel cage is completely embedded in the rotor. In particular, squirrel cage rings with squirrel cage bars made of a first metallic material are sprayed onto the shaft body together with the second metallic material, so that the squirrel cage is completely bonded to the material, thus securing it, for example, against centrifugal forces occurring during operation.

[0027] In a further advantageous embodiment, the first metallic material has a conductivity of more than 40 MS / m. For example, the first metallic material contains copper and / or silver. Such high conductivity reduces electrical losses in the rotor. Since less waste heat is generated, the rotor can be cooled easily and cost-effectively.

[0028] It is particularly advantageous to spray the first metallic material with a first spraying device and the second metallic material with a second spraying device. For example, the materials are sprayed with parameters optimized for manufacturing, such as nozzle diameter, particle size, pressure, and / or temperature, which leads to an improvement in the electrical and mechanical properties of the rotor. Using different spraying devices reduces manufacturing time.

[0029] According to the invention, the metallic materials are sprayed onto the essentially cylindrical outer surface of the shaft body in a rolling motion. Rolling spraying means that the shaft body is rotated about its axis of rotation while the spraying device moves parallel to the axis of rotation. Since the spraying device is not moved in the direction of rotation, it is ensured that the spray particles strike the outer surface of the shaft body at a constant angle. Furthermore, rolling spraying is not only precise but also time-efficient, since the spraying device, which moves rigidly in the axial direction, rarely needs to be realigned.

[0030] The rolling spraying of metallic materials is particularly advantageous when carried out alternately and / or on an involute path. Alternating rolling spraying means that the shaft body remains stationary while the spraying devices move axially and the solid particles are sprayed. The shaft body is then rotated by a small increment while the spraying process is interrupted. The solid particles are then applied again, while the shaft body remains stationary, in an immediately adjacent path parallel to the axis of rotation. Alternating rolling spraying is easy to implement. Rolling spraying on an involute path means that, unlike alternating spraying, the shaft body also moves while the spraying devices move axially and the solid particles are sprayed.Rolling spraying on an involute track accelerates the manufacturing process. A groove chamfer, for example in a cage rotor, is easily implemented.

[0031] In a further advantageous embodiment, a third material is sprayed on in such a way that the metallic materials are arranged in isolation from one another. For example, a rotor with an electromagnet having excitation windings can be manufactured using a thermal spraying process. Such a process is flexible, for example with regard to the number of poles, conductor cross-sections, and number of windings, and is simple due to a reduction in the number of process steps.

[0032] According to the invention, at least two coating materials are positively joined. Such a positive-locking connection can be produced, for example, by means of a rib structure, in particular a sawtooth-shaped one. The positive locking mechanism further stabilizes the rotor.

[0033] The invention will now be described and explained in more detail with reference to the exemplary embodiments shown in the figures.

[0034] They show: FIG 1 a longitudinal section of an electric rotating machine, FIG 2 a side view of a rotor with a squirrel cage, FIG 3 a cross-section of an unclaimed embodiment of a rotor with a coating, FIG 4 a cross-section of another unclaimed embodiment of a rotor with a coating, FIG 5 an enlarged cross-section of an embodiment of a rotor according to the invention with a coating, FIG 6 an enlarged cross-section of a further unclaimed embodiment of a rotor with a coating, FIG 7 a schematic representation of a method according to the invention for manufacturing a rotor and FIG 8 a schematic representation of another method according to the invention for manufacturing a rotor.

[0035] The embodiments described below are both embodiments according to the invention and exemplary embodiments that are not covered by the claims.

[0036] In the embodiments described according to the invention, each component represents an individual feature of the invention that can be considered independently of one another. Each of these features further develops the invention independently and can therefore be considered part of the invention individually or in a combination other than that shown. Furthermore, the described embodiments can also be supplemented by other features of the invention already described.

[0037] The same reference symbols have the same meaning in the different figures.

[0038] FIG 1 Figure 1 shows a longitudinal section of an exemplary rotating electric machine 2, which is designed as an asynchronous machine. The asynchronous machine has a rotor 6 rotatable about an axis of rotation 4 and a stator 8 surrounding the rotor 6. A gap 10, preferably an air gap, is located between the rotor 6 and the stator 8. The axis of rotation 4 defines an axial direction, a radial direction, and a circumferential direction. The rotor 6 comprises a solid shaft body 12 with a coating 14, which includes a magnetic pole-generating element. The magnetic pole-generating element is designed as a squirrel-cage 16. Alternatively, the rotating electric machine 2 is designed as a synchronous machine, wherein the rotor 6 of the synchronous machine has permanent magnets or poles with excitation windings as the magnetic pole-generating element.The stator 8 comprises a magnetic field-carrying stator element 18, which is designed as a laminated core to suppress eddy currents, and a stator winding 20, which forms winding heads 22 at the axial ends of the stator laminated core.

[0039] FIG 2 Figure 1 shows a side view of an exemplary rotor 6 with a squirrel cage 16. The squirrel cage 16 has short-circuit bars 16a, which are connected at their axial ends by a short-circuit ring 16b. The coating 14 is applied by a thermal spraying process and is designed such that the rotor 6 is essentially cylindrical and the squirrel cage 16 is completely embedded in the coating 14 of the rotor 6. Examples of thermal spraying processes are arc spraying, plasma spraying, flame spraying, or cold gas spraying. The solid shaft body 12 is made of a soft magnetic material. The coating 14 comprises a first metallic material and a second metallic material, the second metallic material being a soft magnetic material and essentially corresponding to the soft magnetic material of the shaft body 12.The first metallic material of the squirrel cage 16, for example copper or a copper alloy, has a conductivity of more than 40 MS / m. Furthermore, the coating 14, which encloses the squirrel cage 16, is at least metallurgically bonded to the shaft body 12 by thermal spraying, so that the rotor 6, which has a diameter d of at least 30 cm, can be operated with a power output of at least 1 MW and a rotational speed of at least 10,000 rpm. For example, in cold gas spraying, solid particles accelerated by a gas stream strike the shaft body 12 with such high kinetic energy that a metallurgical bond is formed via diffusion mechanisms. The further design of the rotor 6 is described in... FIG 2 corresponds to the in FIG 1 .

[0040] FIG 3 Figure 1 shows a cross-section of an unclaimed embodiment of a rotor 6 with a coating 14. The coating 14 comprises metallic solid particles which are sprayed onto the substantially cylindrical outer surface 24 of the shaft body 12 by means of cold gas spraying. The coating comprises solid particles of a first metallic material 26 and solid particles of a second metallic material 28, wherein the first metallic material 26 is sprayed directly onto the substantially cylindrical outer surface 24 of the shaft body 12 by means of a first spraying device 30 and the second metallic material 28 by means of a second spraying device 32. The squirrel cage 16 is, as shown in Figure 1, FIG 2 , formed from solid particles of the first metallic material 28. The second metallic material 28 is, as in FIG 2 , a soft magnetic material, for example steel, and essentially corresponds to the soft magnetic material of the shaft body 12. The squirrel cage 16 is completely embedded in the rotor 6. At least the short-circuit bars 16a of the squirrel cage 16 have a sector-shaped annular cross-section. The contour is approximately rectangular or square. Such a rectangular or square contour of the conductors of the squirrel cage 16 results in a high current-carrying capacity. The further design of the rotor 6 in FIG 3 corresponds to the in FIG 2 .

[0041] FIG 4 Figure 1 shows a cross-section of a further unclaimed embodiment of a rotor 6 with a coating 14, wherein at least the short-circuit bars 16a of the short-circuit cage 16 have a rounded contour in cross-section. The contour of the short-circuit bars 16a is shown as a U-shape by way of example. The short-circuit cage 16 is completely embedded in the coating 14 of the rotor 6. Further embodiment of the rotor 6 in FIG 4 corresponds to the in FIG 3 .

[0042] FIG 5 Figure 1 shows an enlarged cross-section of an embodiment of a rotor 6 according to the invention with a coating 14, wherein the first material 26 and the second material 26 are additionally positively connected by a rib structure 34, for example a sawtooth-shaped one. The squirrel cage 16 is completely embedded in the coating 14 of the rotor 6. The further design of the rotor 6 in FIG 5 corresponds to the in FIG 3 .

[0043] FIG 6 Figure 1 shows an enlarged cross-section of another unclaimed embodiment of a rotor 6 with a coating 14. The coating comprises solid particles made of a first metallic material 26, a second metallic material 28, and a third material 36. The materials 26, 28, and 36 are sprayed onto the substantially cylindrical outer surface 24 of the shaft body 12 by means of different spray devices 30 and 32. For clarity, the spray devices 30 and 32 are shown in Figure 1. FIG 6 not shown.

[0044] The third material 36 is an electrically conductive material, for example, silver, brass, zinc, or aluminum, and differs from the first metallic material 26 in its electrical, thermal, and / or mechanical properties. An electrically conductive third material 36, for example, improves the mechanical stability of the rotor 6 and / or reduces losses occurring during operation. The third material 36 is associated with the squirrel cage 16 and connects the first metallic material 26 to the second metallic material 28. Alternatively, the third material 36 is an electrically insulating material, for example, aluminum oxide, and insulates the first metallic material 26 from the second metallic material 28. Further design of the rotor 6 in FIG 6 corresponds to the in FIG 4 .

[0045] FIG 7 Figure 1 shows a schematic representation of a method according to the invention for manufacturing a rotor 6. The coating 14 of the rotor 6 is sprayed onto the substantially cylindrical outer surface 24 of the shaft body 12 by means of cold gas spraying from, for example, two spray devices 30, 32, wherein the spray devices are arranged axially one behind the other and / or next to each other in the circumferential direction.

[0046] The spray devices 30, 32 are operated simultaneously or alternately. According to the invention, the metallic materials 26, 28 of the coating 14 are sprayed onto the shaft body 12 in a rotating manner, which means that the shaft body 12 is rotated about its axis of rotation 4 while the spray devices 30, 32 are moved parallel to the axis of rotation 4. Since the spray devices 30, 32 are not moved in the direction of rotation, it is ensured that the solid particles strike the outer surface 24 of the shaft body 12 at a constant angle of 80° to 110°.

[0047] The rotating spraying of the metallic materials 26, 28 is carried out alternately, meaning that the shaft body 12 is stationary while the spray devices 30, 32 are moved in the axial direction and the solid particles are sprayed. The shaft body 12 is then rotated by a small increment while the spraying process is interrupted. The solid particles are then applied again, while the shaft body 12 remains stationary, in an immediately adjacent path parallel to the axis of rotation. Further design of the rotor 6 in FIG 7 According to the invention, this corresponds to the in FIG. 5

[0048] FIG 8 Figure 1 shows a schematic representation of another inventive method for manufacturing a rotor 6. The rolling spraying of the metallic materials 26, 28 takes place on an involute path, which means that the shaft body 12, in contrast to alternating spraying, also moves while the spray devices 30, 32 are moved in the axial direction and the solid particles are sprayed. To achieve reproducible results, the movements of the spray devices 30, 32 and the rotational movement of the shaft body 12 must be synchronized. The further design of the rotor 6 in Figure 1 FIG 8 According to the invention, this corresponds to the in FIG. 5 In summary, the invention relates to a method for manufacturing a rotor 6 for an electric rotating machine 2 according to independent claim 1.

Claims

1. Method of producing a rotor (6) for an electric rotating machine (2) having at least a shaft body (12) and a squirrel cage (16), where a coating (14) composed of at least one first metallic material (26) and a second metallic material (28) different from the first metallic material (26) is sprayed by a thermal spraying method onto at least part of an essentially cylindrical outer surface (24) of the shaft body (12), where the coating (14) forms at least a part of the squirrel cage (16), characterized in that the metallic materials (26, 28) are sprayed onto the essentially cylindrical outer surface (24) of the shaft body (12) in a rolling manner, where at least two materials (26, 28) of the coating (14) are positively joined.

2. Method according to Claim 1, wherein the thermal spraying method used is cold gas spraying.

3. Method according to either of Claims 1 and 2, wherein the second metallic material (28) is a soft-magnetic material.

4. Method according to any of Claims 1 to 3, wherein the shaft body (12) is made from the second metallic material (28).

5. Method according to any of the preceding claims, wherein the first metallic material (26) forms at least part of a squirrel cage (16).

6. Method according to Claim 5, wherein the squirrel cage (16) is fully embedded in the rotor (6).

7. Method according to any of the preceding claims, wherein the first metallic material (26) has a conductivity of more than 40 MS / m.

8. Method according to any of the preceding claims, wherein the first metallic material (26) is sprayed on with a first spraying device (30) and the second metallic material (28) with a second spraying device (32).

9. Method according to Claim 1, wherein the rolling spray application of the metallic materials (26, 28) is effected alternately and / or along an involute path.

10. Method according to any of the preceding claims, wherein a third material (36) is sprayed on in such a way that the metallic materials (26, 28) are in a mutually isolated arrangement.

11. Rotor (6) for an electric rotating machine (2) having a squirrel cage (16), produced by a method according to any of the preceding claims, wherein a coating (14) composed of at least one first metallic material (26) and a second metallic material (28) different from the first metallic material (26) is sprayed by a thermal spraying method onto at least part of an essentially cylindrical outer surface (24) of a shaft body (12), wherein the coating (14) forms at least a part of a squirrel cage (16), wherein the metallic materials (26, 28) are sprayed onto the essentially cylindrical outer surface (24) of the shaft body (12) in a rolling manner, wherein at least two materials (26, 28) of the coating (14) are positively joined.

12. Rotor (6) according to Claim 11, wherein the rotor (6) is operable at a speed of at least 5000 rpm.

13. Electric rotating machine (2) having at least one rotor (6) according to either of Claims 11 and 12.